Field of the Invention
A disclosure of the present specification relates to a method for transmitting network assistance information and a serving cell base station.
Related Art
A 3rd generation partnership project (3GPP) long term evolution (LTE) that improves a universal mobile telecommunications system (UMTS) has been introduced to a 3GPP release 8. The 3GPP LTE uses an orthogonal frequency division multiple access (OFDMA) in a downlink and a single carrier-frequency division multiple access (SC-FDMA) in an uplink. The OFDM needs to know in order to understand the OFDMA. The OFDM may be used since an inter-symbol interference effect can be reduced due to low complexity. The OFDM converts data to be input in serial into N parallel data and transmits it by carrying N orthogonal sub-carriers. The sub-carriers maintains orthogonally in a frequency dimension. Meanwhile, the OFDMA means a multiple access method to realize multiple accesses by providing a part of the available sub-carrier to each user independently, in a system using the OFDM in a modulation scheme.
Recently, the development of 3GPP LTE-advanced (LTE-A), which is an evolution of 3GPP LTE, has been being completed.
Meanwhile, in LTE/LTE-A, a Multi User-MIMO (MU-MIMO) scheme is used. In the MU-MIMO scheme, one cell uses two pieces of codeword in the same radio resource, which enables to transmit data different with each other to multiple user equipments simultaneously through different layers with each other.
However, in the MU-MIMO scheme, a codeword is used such that interference between UEs is minimized, but there is still interference. Accordingly, it is required to remove interference in order to increase the reception performance of UE.